Lab session 6

Part 2

The properties of acids

ACTIVITY 1

1. Place a piece of blue litmus paper, red litmus paper and universal indicator on a white tile. 

2. Use the dropper to carefully add a drop of dilute sulfuric acid to all three strips of indicator. 

Results: 

-Blue litmus paper turns red

-Red litmus paper turns red

-Universal indicator turns red (pH 4.0): 

Conclusion: Acids turn Blue litmus paper red and Red litmus paper red. Acids change the color of the universal indicator. The pH range of acids is <7. 

ACTIVITY 2

1. Using a clean test tube, add dilute hydrochloric acid to the test tube up to 2cm in height. 

2. Light the Bunsen burner.

3. Carefully slip one piece of magnesium ribbon into the test tube. 

Observations: The magnesium ribbon dissolves and the test tube feels hot to the touch.

4. Using a wooden splint, light it using the Bunsen flame and place it at the mouth of the test tube. 

Observations: When the wooden splint was placed in the test tube, a "pop" sound was produced. 

ACTIVITY 3

1. Using a clean boiling tube, add dilute hydrochloric acid to the test tube up to 2cm in height. 

2. Pour calcium carbonate into another test tube up to 2cm in height. 

2. Prepare a set up according to the diagram:

3. Add a spatula of sodium carbonate to the acid in he boiling tube. 

4. Fix the rubber stopper of the delivery tube on the mouth of the boiling tube and place the other end into the test tube containing calcium carbonate.

Observations: A white precipitate is formed and the calcium carbonate (limewater) turns cloudy.